Otto c



0. C. ROHDE.

SPARK PLUG.

APPLICATION FILED APR. 22. ms.

Patented Aug. 19, 1919.

INVEN'TUE 620M.

o'r'ro in. mm, OF

TOLEDO, OHIO, ASSIGNOR T0 CHAMPION SPARK PLUG COMPANY, OF

TOLEDO, GHIO, A CORPORATION OF DELAWARE.

SPARK-PLUG.

Specification of Letters Patent.

Patented Aug. 19,1919.

Application filed 41111122, 1918. Serial No. 230,114.

To all whom it may concern Be it known that I, OTTO C. Ronon, a citizen of the, United States, and a resident of Toledo, in the county of Lucas and State of Ohio, have invented a certain new and useful Spark-Plug; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in'the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the characters of reference marked thereon.

This invention relates to spark plugs for internal combustion engines, and particu larly to spark plugs of the heavy duty type.

The object of my invention is the pro vision of a spark plug having its insulator built up in such manner as to prevent or reduce to a minimum the liability of short circuiting the electric ignition circuit through any part of the insulator, thereby particularly adapting the plug for use in high speed motors, or for heavy duty purposes. i

The invention is fully descr1bed.1n the following specification, and a central longitudinal section of a spark plug embodying the sameis illustrated in the accompanying drawing.

Referring; to the drawing, 1 designates the shell or casing of asparl: plug, which shell is provided with. the customary threaded nipple 2 at its inner end and with the annular internal reducing shoulder 3 adjacent to the inner end of the ni ple 2 and with the annular internal shou der l at the outer end of the'nippler 5 is the customary electrode, which is grounded through the shell or casing, and 6 is the center electrode which .may be of nickel, manganese, or other-suitable material and is carried bythe current conducting spindle 7 projecting axially through the shell and preferably provided with an enlargement 8 forming an annular shoulder at its inner or electrode carrying end to which the electrode 6 is attached if the electrodes and spindle are made in separate pieces. The spindle 7 is rigidly carried within the shell 1 and effectively insulated therefrom by an insulator, .the construction and arrangement of the parts of which will now be described.

An insulator sleeve 9 of tubular form and preferably comprising a plurality of thin cylinders or tubes of mica or other suitable insulating material, closely fitted one within another, is fitted closely within the shell and extends from the shoulder 3 to adjacent to the outer end of the shell. A similar sleeve 10- is fitted closely within the nipple 2, extending inward from the shoulder 4 a distance beyond the shoulder 3 in lapping relation to the adjacent end of the sleeve 9 but radially spaced therefrom. An insulating sleeve 11, similar in construction to the sleeves 9 and 10, closely embraces tthe spindle 7 and extends from near the louter end of the spindle to near the enlargeinent 8 thereon, but preferably in longitudinally spaced relation to such enlargement and a short distance within the inner end portion of the sleeve 10 in radially spaced relation thereto. A tubular insulating lining 12, preferably, but not necessarily composed of mica, is fitted closely within the sleeve 10 and extends from the shoulder 4 to the end of the center sleeve 11 in close end abutment with each. The inner end portion of this lining completely fills the space between the spindle 7 and sleeve 10 from the sleeve 11 to the spindle enlargement or shoulder 8 and thence has its opening enlarged to receive the spindle or chamber 13 around the electrode. A tubular lining member 14, preferably built u in laminated form of mica washers, is tted between the sleeves 9 and 11 and extends from the outer end of .the sleeve 9 substantially flush therewith to the inner end of the sleeve 10 on which it seats and is provided at such inner end with the two annular leg portions 15 and 16', the former fitting within the space between the adjacent end portions of the sleeves 10 and ll and against theinner end of the lining member 12, and the latter fitting within the space between the adjacent end portions of-the sleeves Qand 10 and seating on the shoulder 3.

A metal collar 17 which may be of-steel, brass or other suitable material, is preferably fitted within the outer end portion of the shell 1 around the spindle sleeve 11 and against the adjacent endsof the sleeve 9 and lining member 14. This collar forms a firm seat over which the outer edge portion 18 may be turned to retain the insulator parts llltl within the shell in rigid assembled relation. A sleeve 19 of insulating material, whlch may comprise a plurality of mica washers built up in laminated form, encircles the outer end portion of the sleeve 11 withoutthe collar 17 and extends from such collar to a point slightly beyond the outer end of the sleeve 11, where it receives the thrust of a binding nut 20 through the medium of a washer 21, said nut being threaded on the outer end portion of the spindle. A look nut 22 is threaded on the spindle 7 without the nut 20 and a terminal binding nut 23 is threaded 0n the spindle without the nut 22 to cooperate therewith to bind a wire terminal. v 7

It is evident that the forcing of theshell edge 18 over on the outer edge of the thrust collar 17 exerts a longitudinal thrust throughsaid collar and on to the interior lnsulating parts, with the exception of the sleeve 11, and forces the laminations of the members 12, 14, 15 and 16 closely together i and against the respective abutting shoulders 3 and 4 of the shell, and that the'tightening of the jam nut 20 on the spindle 7 forces the insulating member 19 against the collar 17, and at the same time exerts an ou t* ward pull on the spindle 7 to tighten its enlargement 8 against the shouldered portion of the insulating member 12.

It is also evident that the sleeve 9 laps the inner end of the sleeve 11 and that the sleeve 10 laps the inner ends of both the sleeves 9 and 11, thus preventing any possibility of a short c rcuit taking place between the shell and splndle around the ends of said sleeves through spaces which may occur between some of the lamina of the insulating members 12, 14,15 and 16.- It is found in practice that this plug is highly eflicient for use in high speed or heavy duty motors, in which considerable trouble has been experienced by reason of short-circuiting takin lace between the shells and spindles o t e spark plugs.

While I have particularly referred to laminated m1ca as being used as the insulating material, the invention is not restricted to the use of such material, as it contemplates the use of any other suitable insulatin mater1al, whether of solid or laminated orm. I wish it understood that my invention is not limited to any specific form or ar-.

rangement of the parts, as his capable of numerous modifications without departing from the spirit of the claims.

Having thus described my invention, what I I claim as new and desire to secure by Letters Patent, is

1. In a spark plug, a shell, an electrode spindle passing through the shell, and an insulator carrying the spindle and having an insulator sleeve fitting the spindle, separate 1nsulator sleeves fitting different portions of the shell, said sleeves extending longltudlnally of .the spindle andlapping lator having wit in the. shell three.longitudinally extending sleeves which fit the spindle and the different portions of the shell in lapping relation one to another, and insulator members, cooperating with said sleeves to insulate thespindle and shell.

3. In a spark plug, a shell having a pluralit of shoulders, an electrode spindle passing through said shell and having an enlargement within the electrode end portionlof the shell, and an insulator carrying said spindle, said insulator having within the shell three longitudinally extending insulating sleeves some of which seat on sald shoulders and having insulating filling members seating on said shoulders and spin- .dle enlargement and cooperating with said sleeves to insulate the spindle and shell, said sleeves lapping each other in radially spaced relation.

4, In a spark plug, a shell having internal shoulders, an electrode spindle passing through said shell and having an enlargement adjacent to its electrode end, an insulator rigidly connecting said spindle and shell, said .insulator having an insulating sleeve fitting-the spindle and extending from without the outer end of, the shell to adJacent to the spindle enlargement, insulatlng sleeves fitting different portions of said shell and lapping each other and the inner end of said spindle sleeve, insulating means filling the spaces between said sleeves and cooperating therewith to insulate the shell and spmdle a thrust member disposed in the outer end portion of the shell, and engaged by the shell to cooperate therewith to retain the interior insulating sleeves and members in assembled relation and seated on the shoulders, an insulating collar without said thrust member encirclin the outer end of said spindle sleeve, an means'on the outer end of the spindle cooperating therewith and with the spindle enlargement to secure the insulator parts in assembled relation'on the spindle.

5. In a sparkplug, a shell, having a reduced nipple at its inner end and provided with internal shoulders adjacent to the inner and outer ends of said nipple, anele'ctrode spindle passing through said shell, an i'nsulating sleeve fitting within the large portion of the shell and extending from the inner one of said shoulders adjacent to the outer end of the shell, a. second insulating sleeve fitted Within the shell nipple and extending from the outer one of said shoulders to a distance beyond the inner shoulder in lapping relation to said first sleeve, a third insulating sleeve fitting said spindle and extending from adjacent the outer end of the spindle to adjacent the inner shoulder of the shell i and in lapping relation to both said first and second mentioned sleeves, insulating filling members cooperating With said sleeves to insulate the spindle from the shell, a thrust member fitted within the outer end portion of the shell and cooperating therewith to force said first and second sleeves and said filling members against respective shoulders Within the shell, an insulating collar encir- 5 cling the spindle sleeve Without said thrust member,- and means on the spindle for clamping it to' the insulating members mounted thereon. v

6. In a spark plug, a shell, having an internally reduced nipple at its inner end and provided with internalshoulders adjacent to the inner and outer ends of said nipple, an

electrode spindle passing through said shell,

'- an insulating sleeve fitting within the large portion of the shell and seating at its inner end on the inner shoulder, a second insulating sleeve fitting Within the nipple-and extending from the outer one of said shoulders to a distance beyond the inner shoulder in radiallyspaced lapping relation to'said first sleeve, a third insulating sleeve fitting said spindle and having its inner end extending beyond the inner end of said second sleeve in radially spaced lapping relation thereto, insulating filling means filling the spaces between said sleeves, and means cooperating with the spindle to secure said sleeves and filling means in assembled relation. I

7 In a spark plug, a shell, having its bore reduced at its inner end and provided with internal shoulders at'the inner and outer ends of the reduced portion, a spindle extending through said shell, separate insulating Sleeves fittin within the large and re-- 1 'duced portions or said shell with their adjainner side of the sleeve which fits into the small portion of the shell bore, and means for securing said insulating parts in assembled relation.

In testimony whereof, I have hereunto signed my name this specification. 

